Alton Brown: Best Ever Green Bean Casserole

Holy, schmoly, I think I've found the holy grail of Thanksgiving dishes.  Heck, let's just be honest, the holy grail of casseroles.  I thought I was going to be eating canned soup versions of this casserole for all eternity, but here it is, a homemade version.  A green bean casserole that is just as savory and umami and tender and crunchy and fantastic as the original, and yet, something more.  The green beans have a freshness, and the mushrooms have a texture (other than cooked-to-death). You MUST make this for your Thanksgiving dinner.  MUST.

Best Ever Green Bean Casserole
Adapted from Alton Brown

For the topping:
2 medium sweet onions (about 1¼ pounds), thinly sliced
¼ cup all-purpose flour
2 tablespoons panko bread crumbs
1 teaspoon kosher salt
⅛ teaspoon cayenne pepper
Canola oil, for frying

For beans and sauce:
2 tablespoons plus 1 teaspoon kosher salt, divided
1 pound fresh green beans, rinsed, trimmed and halved
2 tablespoons unsalted butter
12 ounces cremini mushrooms, trimmed and cut into ½-inch pieces

½ teaspoon freshly ground black pepper
2 cloves garlic, minced
¼ teaspoon freshly ground nutmeg
2 tablespoons all-purpose flour
1 cup chicken broth
1 cup half-and-half

Combine the onions, flour, panko, salt, and cayenne pepper in a large mixing bowl and toss to combine. Pour about ¼-inch of oil in the bottom of a large skillet.  Heat over medium-high heat until shimmering.  Add the onions in batches, using a fork to toss them and keep them from sticking together.  Fry for 4 to 6 minutes per batch, or until golden brown. Once done, remove the onions from the pan and drain on a paper towel.  Set aside until ready to use.

Preheat the oven to 375°F.

Bring a gallon of water and 2 tablespoons of salt to a boil in an 8-quart saucepan. Add the beans and blanch for 5 to 10 minutes, depending on how tender you want your beans. Drain in a colander and immediately plunge the beans into a large bowl of ice water to stop the cooking. Drain and set aside in a large bowl.

Melt the butter in a 12-inch skillet set over medium-high heat. Add the mushrooms, 1 teaspoon salt, and pepper and cook, stirring occasionally, until the mushrooms begin give up their liquid, approximately 4 to 5 minutes. Add the garlic and nutmeg and continue to cook for another 1 to 2 minutes, or until the liquid has mostly evaporated. Sprinkle the flour over the mixture and stir to combine. Cook for 1 minute. Add the broth and simmer for 1 minute. Decrease the heat to medium-low and add the half-and-half. Cook until the mixture thickens, stirring occasionally, approximately 6 to 8 minutes.

Remove from the heat and stir in ¼ of the onions and pour over the green beans. Mix together and pour the green bean mixture into a casserole dish.  Place into the oven and bake until bubbly, approximately 15 minutes.  Remove the casserole from the oven, top with the remaining onions, and return to the oven for another 5 minutes.  Remove and serve immediately.

Makes 4 to 6 servings